Multi-story buildings provide numerous advantages, most obvious of which is the placement of a large number or commercial or residential tenants on a premier plot of land. Peculiar to such buildings are the complex electrical wiring systems required to service present as well as future tenants. Further complicating the requirement is the diversity of electrical systems available and the necessity of customizing the system to meet the needs of a particular tenant. Methods of wiring common electrical systems include the use of insulated wires and cables in raceways, non-metallic sheathed cables, metallic armored cables, busways, copper jacketed or mineral insulated cables, aluminum sheathed cables, nonmetallic sheathed and armored cables in cable support systems, and open insulated wiring on solid insulators, hereinafter referred to as wires or cables. Insulated conductors may be installed in a rigid metal conduit, flexible metal conduit, electric metallic tubing, liquid tight flexible metal conduit, surface metal raceways, underfloor raceway, cellular floor raceway, rigid non metallic conduit and raceways, hereinafter referred to collectively as raceways.
Obviously the electrical conductors must be housed in one of the above mentioned raceways. The problem with placing raceways between floors of a multi-story building is that a fire may spread from floor to floor using the raceway as its connection. Due to this possibility, building codes typically require that the floor/ceiling or barrier is constructed of a fire proof material, such a concrete. In addition, any holes placed in the barrier, such as for the raceway, must have the annular space around the raceway filled with a noncombustible penetrating material to prevent the spread of fire.
U.S. Pat. No. 4,261,598 discloses the use of coupling joints cemented into the floor/ceiling during formation of the floor/ceiling. The result is a cast-in-place pipe.
U.S. Pat. No. 4,901,488 issued to Murota et al., discloses the use of thermal expansion composite molded members that are each molded into a desired shape to fill in the void defined between an inner surface plastic pipe and an outer surface of a plastic pipe. Murota is limited to sealing of the pipe in lieu of concrete fillers.
U.S. Pat. No. 4,916,800 issued to Harbeke discloses the use of a fire retardant fluid coupling method. The disadvantage of this device is that it is essentially a coupling, thus a raceway placement must juncture at the coupling. If the installer cuts the raceway to conform to the location of the coupling and does not exactly measure the correct distance, the raceway becomes waste. If the installer is desirous of saving a raceway cut incorrectly, an additional coupling must be fitted causing additional labor and material expense.
What the prior art teaches is a means for coupling the raceway at the floor/ceiling juncture resulting in a partially hidden or otherwise inaccessible coupling location. Thus, the coupling location increases the possibility of a poor connection, incorrectly sized raceway, or other limitations well documents in the prior art which teaches to avoid the use of raceways cast as part of the floor/ceiling juncture. If the coupling must be replaced and the coupling is made integral with the concrete, the result is a costly rework. Finally, use of a combination coupling/fire retardant device limits the type of raceway to that compatible with the coupling/fire retardant device. All other prior art teaches the formation of a fire barrier around a cast-in pipe effectively teaching away from using a raceway within a sleeve, or larger raceway, thereby allowing the installer freedom of assembly.
What is needed in the art is a device or apparatus that allows for raceway coupling remote from the floor/ceiling fire-retardant barrier thus expediting the installers time, preventing the waste of materials, and preventing ineffectual coupling due to forced couplings at partially hidden or inaccessible locations. It is, therefore, to the effective resolution of the aforementioned problems and shortcomings that the present invention is directed.